Method of chlorinating titanium bearing materials



June 3109 i941. a, E. MUSKAT ETAL METHOD OF CHLORINATING TITANIUMBEARING MATERIALS Filed May 4, 1940 INVENTOR. IRVNG E. MUSKAT ROB BY ERTTAYLOR ATTORNEY.

Patented June 10, 1941 UNITEDA STATE METHOD F CHLORINATING TITANIUMBEABIN G MATERIALS Irving E. Muskat and Robert H. Taylor, Akron,

Ohio, assignors to Pittsburgh Plate Glass Company, Allegheny County,Pa., a corporation oi' Pennsylvania Application May 4, 1940, serial No.333,361

' (cl. 'z5- 111) 18 Claims.

This invention relates to the chlorination of ores containing iron andtitanium and to the recovery of the chlorides of these metals. Thechlorination of such materials may be conducted in a manner such that amixture of iron and titanium chlorides are formed and volatilized. Priorto applicants invention, attempts were made to separate and recover thetwo chlorides by means .of fractional condensation. These processes havebeen found to be unsuccessful since plugging of the condenser systemoccurs Within a short time after the process has been initiated.

In accordance with our invention; we have provided a method ofrecovering the iron and titanium chlorides without the pluggingdiiiiculties which have been encountered in prior art processes. Theinvention is particularly applicable to the treatment of vapors producedby the chlorination process described in our'Patent No. 2,184,887.

In accordance with this process, we have found that the chlorination maybe conducted Without recourse to an externally heated reactor and thatplugging may be substantially eliminated. 'I'he process is adapted tothe treatment of titanium bearing materials containing from.- to-50percent or more of titanium and up to 50 percent of iron and isparticularly adapted to the treatment of titanium bearing ores such asilmenite which contain 20 to 50 percent of titanium and 10 to 40 percentof iron. Other ores such as titanomagnetite or other titanium ironbearing materials such as ferrotitanium, etc., may also be chlorinated.

The chlorination may be conducted in th presence of the required amountof a reducing agent such as carbon, if desired, in a suitable furnacewith the consequent production of vapors of iron chloride and titaniumtetrachloride. These vapors may be condensed and the chlorides thereinseparated as hereinafter described. We

when an ore such as 'ilmenite is chlorinated at a temperature of about700 C., or`above, the temperature of reaction may be maintained throughcareful periodical observation of temperature and regulation of the rateof introduction of chlorine, ore and carbon. ln such a case, it is foundpossible to secure a good utilization of the chlorine introduced and tosecure chlorination. of the major portion of the ore without difficulty.When the temperature is maintained at 850l250 C., maintenance oftemperature within the reactor is considerably easier and lessadjustment of the rate of addition of ore, carr bon and chlorine isrequired. In addition, the

have found that if the chlorination is conducted at a temperature not.less than 600 C. and preferably above 700 C., the reaction proceedswith such rapidity that the heat evolved by the reaction is suiiicientto maintain reaction temperature Without externally heating the reactor.Thus, by regulating the rate of introduction of ore, carbon and chlorineinto the reactor, it is possible to maintain the temperature therein.This is not possible when the chlorination temperature is below 600 C.In order to achieve optimum efiiciency and yield, the temperature shouldbe maintained above 700 C.. maximum efficiency being secured at 8501250C. 'Thus,

chlorine utilization under such conditions generally exceeds percent andin excess of 80 percent of the ore is generally chlorinated.

In the treatment of ores such as ilmenite, itl

bon concentrations below 15 percent by weight of the ore are insuicientto insure complete chlorination of the iron and titanium components. Onthe other hand, excess carbon concentrations are found to beobjectionable since the presence of the excess makes temperaturemaintenance diicult. For most purposes, the carbon concentration shouldbe maintained at 15-35 percent by weight of the ore. We have found thatwithin limits the amount of titanium volatilized is proportional to theamount of carbon present. Thus, when an ilmenite ore containing 35.2percent of titanium and 25.8 percent of iron is mixed With 2` to 6percent of carbon and chlorinated at high temperatures, for example,above 850 C., substantially all of the iron is volatilized as ironchloride leaving the titanium in the form of an oxide in the residue. Asthe carbon concentration is increased, more and more titanium may bevolatilized as the tetrachloride by chlorination and when the carbonconcentration is 15 to 35 percent of the ore, in excess of 80 percent ofthe ore is completely chlorinated. Further increases in carbonconcentration do not appear to increase the efficiency of thereactionbut on the contrary, exert a quenching effect upon the reaction, thusmaking temperature maintenance very diilicult. This may be compensatedfor to a degree by introduction of air or oxygen with the chlorine intothe furnace in order to burn the excess carbon with consequent evolutionof heat. l

The vaporsthus produced comprise a mixture of -iron and titaniumchlorides, wherein the iron chloride concentration generally exceeds 20percent by weight of the weight of titanium tetrachloride in the vapors.

In general, it is difficult to secure sa-tisfactory separation of theiron chloride by fractionally condensing iron and titanium tetrachloridesince iron chloride often distributes itself throughout the condensersystem, plugging the system to such an extent that it must be cleaned atfrequent intervals. In order to avoid this plugging, it is advisable tocondense the major portion of the iron chloride shortly after it iswithdrawn from the furnace. To insure the removal of iron chlorides tosuch an extent that the possibility of plugging during subsequentcondensation processes is'minimized, it is found desirable to condenseout allor a portion, generally not less than about -30 percent of thetitanium tetrachloride together with the iron chloride. Any residualtitaniumtetrachloride vapor may then be condensed without fear ofplugging the condenser system.

We have found that when a fractional condensation of iron chloride isattempted, a large portion of the iron chloride remains dispersed intheuncondensed gases in the form of a finely divided smoke or solidsuspension. When a substantial portion of titanium tetrachloride iscondensed with the ferric chloride, however, the condensed liquidtetrachloride bathes the gases and assists separation of Ithe solidferric chloride therefrom. 'I'he mixture of 4chlorides so condensed maythen be heated to recover the titanium tetrachloride. In order toimprove the separation of iron and titanium chlorides, it is desirableto heat the condensed mixture in the presence of a gaseous diluent. I'hegaseous mixture which remains after condensation of iron chloride andpart of the titanium tetrachloride is found to be particularly suitablefor a diluent since it is substantially free from oxygen or otheragen-ts which would promote decomposition of the chlorides.

This process is particularly applicable to the treatment of vaporscontaining a large amount of iron chloride whereby when iron and ttanumchlorides are condensed, a condensate which is solid or at least in theform of a thick fluid mush is obtained. 'I'his mixture thus obtainedcon-y tains a substantial quantity of iron chloride, the concentrationgenerally being in excess of 20 percent by weight of the total mixture.Since such mixtures ordinarily cannot be ltered, the

titanium tetrachloride is generally removed by heating the mixture torevaporize the titanium tetrachloride. To insure eilicient vaporizationof the tetrachloride, this trea-tment preferably should be conduced byheating the chlorides to a temperature of 100-250 C. in the presence ofa gaseous diluent such as nitrogen, chlorine, carbon dioxide, etc., inorder to increase the volatility of the titanium tetrachloride. Thisprocess has ,been conducted most efficiently by transferring thecondensed mixture of chlorides by scrapers or other suitable means toanother portion of the condenser system and vaporizing the tetrachloridein the mixture in the presence of the mixture of gases which may containchlorine,

carbon dioxide, and vaporized titanium tetrachloride from whichcondensed chlorides were obtained initially. This may be done, forexample, by preliminarily heating this gaseous mixture and contactingthe condensed mixture of chlorides with the heated gases.

'I'he accompanying drawing diagramma-tically illustrates ya suitableapparatus for conducting the process in accordance with our inventionThe apparatus comprises a pair of condensers I and I I, which may be aircooled or may be coolec by water as will be understood in the art. Inth( normal operation of this device, ore or othel titanium bearingmaterial is chlorinated in s suitable furnace such as shownin our PatentNo. 2,184,887, or other suitable furnace anc vapors of iron and titaniumchloride are formed These vapors are introduced through inlet conduit I,into condenser 2, which is provided with a water jacket 3, where theyare cooled to a temperature suiiiciently low, for example, below 40 C.,whereby the major portion of the iron chloride and a large quanti-ty oftitanium tetrachloride are condensed and collected as a slush in chamberB, at the base of condenser I. Clogging of the condenser is prevented bymeans of a traveling chain 4, upon which are mounted scrapers 5. Thechlorides are conveyed by these scrapers or by gravity to chamber 6,beingdischarged upon a floor 9. This condensate is then conveyed alongthe floor by meansof scrapers 8, which are mounted upon a travelingchain 1, and are thus moved toward the end of the chamber. The chamberis heated by a suitable means I6, to the temperature required to permitvaporization of titanium tetrachloride, for example, to 250 C. Thisvaporization is assisted by contact of the diluent gases escaping fromthe bottom of condenser 2, which pass over the condensate.

The ferric chloride, after vaporization of titanium tetrachloride, isdischarged to the bottom of chamber 6, and finally is conveyed to aferric chloridey outlet II, by scrapers 8. The vapors passing fromchamber 6 enter titanium tetrachloride spray condenser II, Ithroughconduit I0, Where they are sprayed with a liquid halide such as titaniumtetrachloride which is supplied to sprayhead I4, through supply line I8.'Ihe vapors are thus washed to remove suspended iron chloride and aportion or all of the titanium tetrachloride is condensed and collectedin reservoir I2. The exhaust gases are removed through outlet I5, andmay be subjected to further con densing operations for recovery ofuncondensed titanium tetrachloride. Titanium tetrachloride may bewithdrawn periodically through outlet; I3. In order to assist in therevaporization of titanium tetrachloride, a gaseous diluent such ascarbon dioxide, nitrogen, etc. may be introduced through inlet I9, intochamber 6. If desired, the gases passing through chamber 6 may besprayed with a liquid halide such as titanium, carbon or silicontetrachloride, by means of suitable sprays (not shown) in order toinsure complete removal of the iron chloride from the system. Thisliquid may be revaporized with the previously condensed titaniumtetrachloride and recovered in subsequent operations.

The following example illustrates the invention as applied to ilmeniteore. ores may be treated in similar manner.

Erample.-Using a shaft furnace having an internal diameter of 15 incheswhich was preheated to a temperature of 1000 C., briquettes preparedfrom a mixture corresponding to 100 parts ore to 23 parts C to 14 partsmolasses were introduced at a rate of pounds per hour and chlorine at2.0 to 2.5 pounds per minute. The temperature remained at 8501000 C.throughout the run without externally heating the furnace. The vaporswere withdrawn from the furnace and cooled to 40 C. whereuponsubstantially all of the ferric Other iron titanium chloride and 25 percent of the titanium tetrachloride were simultaneously condensed. Thecondensed chlorides lwere transferred to another portion of thecondenser where the titanium tetrachloride was revolatilized by heatingwhile passing the exhaust gases of the furnacev over the furnace at aconstant level.

Although the present invention has been de' scribed with reference tospecific details of certain embodiments thereof, it is not intended thatsuch details shall be regarded as limitations upon the scope of theinvention except insofar as included in the accompanying claims. 'I'hisapplication is a continuation-in-part of our copending applicationsSerial Nos. 205,323, illed April 30. 1938and 282,199, led June 30, 1939.

We lclaim:

.1. In the chlorination of a titanium bearing material which contains aquantity of iron of such magnitude that upon chlorination of saidmaterial, the amount of iron chloride formed is such as to causeplugging of the condenser system and at least l percent of titanium, theprocess which comprises chlorlnating the material at a temperaturesuiiiciently high to volatilize iron chloride and titanium tetrachlorideto form a vapor mixture containing a large quantity oi both iran andtitanium chlorides, initially condensing the major portion of the ironchloride from the vapor mixture together with a quantity of titaniumtetrachloride in an amount sufficient to insure the elimination of themajor portion of the condensed iron chloride from the vapor mixture andthus to minimize the tendency toward plugging of the system andseparately condensing a further quantity of titanium chloride from thevapor mixture.

2. In the chlorination of a titanium bearing material which contains aquantity of iron of such magnitude that upon chlorination of saidmaterial, the amount of iron chloride formed is such as to causeplugging of the condenser system and at least percent of titanium, theprocess which comprises chlorinating the material at a temperaturesuiiiciently high to volatilize ircn chloride and titanium tetrachlorideto form a vapor mixture containing a large quantity of both iron andtitanium chlorides, initially condensing the major portion of the ironchloride from the vapor mixture together with a quantity of titaniumtetrachloride in an amount sufficient to insure the elimination of themajor portion of the condensed iron chloride from the vapor mixture andthus to minimize the tendency toward plugging of the system and heatingthe resulting condensed mixture in the presence of a. gaseous diluent ata low temperature to vaporize titanium tetrachloride from the ironchloride.

3. In the chlorination of a titanium bearing material which contains aquantity of iron of such magnitude that upon chlorination of saidmaterial, the amount of iron chloride formed is such as to causeplugging of the condenser system and at least l0 percent of titanium,the process which comprises chlorinating the material at a temperaturesuiciently high to volatilize iron chloride and titanium tetrachlorideto form a vapor mixture containing a large quantity of both iron andtitanium chlorides, initially condensing the major portion of the ironchloride I from the vapor mixture together with a quantity CFI cri!4titanium tetrachloride in an amount sumcient to insure the eliminationof the malor'portion of the condensed iron chloride from the vapormixture and thus to minimize the tendency toward plugging of the systemand heating the resulting condensed mixture in the presence of a portionof the unoondensed vapor to volatilize titanium tetrachloride.

4. In the chlorination of a titanium bearing material which contains aquantity of iron of such magnitude that upon chlorination of saidmaterial, the amount of iron chloride formed is such as to causeplugging of the condenser system and at least 10-percent of titanium,the process which comprises chlorlnating the material at a temperaturesumciently high to Volatilize iron chloride and titanium chloride toform a. vapor mixture thereof containing a large quantity of both ironand titanium chlorides, initiallycondensing the major portion of theiron chloride from the vapor mixture together with a quantity oftitanium tetrachloride in an amount suiilcient to insure the eliminationof the major portlon'of the condensed iron chloride and thus theminimize the tendency toward plugging of the system and heating theresulting condensed mixture in the presence of gaseous chlorine at a lowtemperature to vaporize the titanium tetrachloride from the ironchloride.

5. In the chlorination of a titanium bearing material containing inexcess of 10 percent of titanium and in excess of 10 percent of iron,the process which comprises chlorlnating the material at a temperaturesuillciently high to vola.-`

the major portion of the condensed iron chloride from the vapor mixtureis insured and the tendency toward plugging of the system. is minimized,and heating the resulting condensed mixture in the presence of afdiluentat a low temperature to vaporize titanium tetrachloride from the ironchloride.

6. In the chlorination oi ilmenite ore the process which compriseschlorlnating the ore at a temperature sufliciently .high to volatilizeiron chloride and titanium tetrachloride to form a vapor mixturecontaining a large quantity of both iron and titanium chlorides,condensing the major portion of the iron chloride from the vapor mixturetogether with a quantity of titanium tetrachloride in an amount sucientto insure the elimination of the major portion of the con densed ironchloride from the vapor mixture and thus to minimize the tendency towardplugging of the system and separately condensing a further quantity oftitanium ohio-ride from the vapor mixture.

7. Inthe chlorination of ilmenite ore the process which compriseschlorlnating the ore at a temperature suiliciently high to volatilizeiron chloride and titanium tetrachloride to form a vapor mixturecontaining a large quantity of both iron and titanium chlorides,condensing the maior portion of the iron chloride from the vapor mixturetogether with a quantity of titanium tetrachloride in an amount suicientto insure the elimination of the major portion of the condensed ironchloride from the .vapor mixture and thus to minimize the tendencytoward plugging of the system, and heating the resulting condensedmixture in the presence of a portion of uncondensed vapor to volatilizetitanium tetrachloride.

8. In the chlorination of a titanium oxide bearing material containingin excess of percent oi titanium and in excess of 10 percent of iron,the process which comprises chlorinating the material at a temperaturesufficiently high to volatilize iron chloride and titanium tetrachlorideto form a vapo!` mixture thereof, condensing the major portion of theiron chloride from the vapor mixture together with at least 15 percentof the titanium tetrachloride whereby the elimination of the majorportion of the condensed iron chloride from the vapor mixture is insuredand the tendency toward plugging of the system is minimized, and heatingthe resulting condensed mixture in the presence of a portion of theuncondensed vapor to volatilize titanium tetrachloride.

9. A method of separating iron and titanium chlorides from a vapormixture containing substantial quantities of both chlorides whichcomprises condensing the major portion of the iron chloride from thevapor mixture together with a quantity of titanium tetrachloride in anamount suiiicient to insure the elimination of the major portion of thecondensed iron chloride from the vapor mixture and thus to minimize thetendency toward plugging ofv the system, and subsequently separatelycondensing the remainder of the titanium tetrachloride.

10. A, method of separating iron and titanium chlorides from a vapormixture containing substantial quantities of both chlorideswhichcomprises introducing the vapor mixture into a condensing system,condensingl the major portion of the iron chloride from the vapormixture together'with a quantity of titanium tetrachloride in an amountsuiiicient to insure the elimination of the major portion of thecondensed iron chloride from the vapor mixture in one portion of thesystem, moving the condensed mixture of iron and titanium chloride to azone of higher temperature within the condenser systemfand heating thecondensed mixture to vaporize the titanium tetrachloride from the ironchloride.

11. A method of separating iron and titanium chlorides from a vapormixture containing substantial quantities of both chloridc-s whichcomprises condensing the major portion of the'iron chloride from thevapor mixture together with a quantity of titanium tetrachloride in anamount sumcient to insure the elimination of the major portion of thecondensed iron chloride from the. vapor mixture and thus to minimize thetendency toward plugging of the system, spraying the residual vapormixture with liquid titanium tetrachloride to assist elimination o flsolid iron chloride therefrom and heating the condensed mixture tovaporize the titanium tetrachloride from the iron chloride.

12. A method of separating titanium and iron chlorides from a vapormixture containing substantial quantities of both chlorides whichcomprises condensing the major portion of the iron` chloride from thevapor mixture together with a quantity of titanium tetrachloride in anamount suiiicient to insure the eliminationoi the mav jor portion of thecondensed iron chloride from the vapor mixture and thus to minimize thetendency toward plugging of the system, spraying the residual vapormixture and the condensed solids with liquid titanium tetrachloride toassist elimination of solid iron chloride therefrom and heating thecondensed mixture to vaporize the titanium tetrachloride lfrom the ironchloride.

y 13. A method of separating iron and titanium chlorides from a vapormixture containing substantial quantities of both chlorides whichcomprises condensing the major portion of the iron chloride from thevapor mixture together with a quantity of titanium tetrachloride in anamount suilcient to insure the elimination of the major portion of thecondensed iron chloride from the vapor mixture and thus to minimize thetendency toward plugging of the system, spraying the residual vapormixture with liquid halide to assist elimination of solid iron chloridetherefrom and heating. the condensed mixture to vaporize the titaniumtetrachloride from the iron chloride.

14. A method of separating titanium and iron chlorides from a vapormixture containing substantial quantities of both chlorides whichcomprises condensing the major portion of the iron chloride from thevapor mixture together with a quantity of titanium tetrachloride in anamount suilicient to insure the elimination of the major portion of thecondensed iron chloride from the vapor mixture and thus to minimizev thetendency toward plugging of the system, spraying the residual vapormixture and the condensed lsolids with liquid halide to assistelimination tion of a condenser, condensing the major portion of theiron chloride from the vapor mixture together with at least a portion oftitanium chloride, moving the condensate from the point of condensationto a zone 4of higher temperature within said condenser and heating saidzone'to vaporize titanium chloride.

16. A method of separating iron and titanium chlorides from a vapormixture thereof which comprises introducing said mixture into one portion of a condenser, condensing the major portion of the iron chloridefrom the vapor mixture together with at least a portion of titaniumchloride, moving the condensate from the point of condensation to a zoneof higher temperature within said condenser, heating said zone tovaporize titanium chloride and passing the uncondensed portion of themixture over the condensate to assist in such vaporization.

17. 'I'he process of claim 16 wherein the condensate and the uncondensedvapors are in concurrent contact.

18. 'I'he process of claim 16 wherein the vapors after passing incontact with the condensate are sprayed with a liquid halide. f

IRVING E. MUSKAT. ROBERT H. TAYLOR.

